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[SPARC64]: Top-down address space allocation for 32-bit tasks.

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Currently allocations are very constrained for 32-bit processes.
It grows down-up from 0x70000000 to 0xf0000000 which gives about
2GB of stack + dynamic mmap() space.

So support the top-down method, and we need to override the
generic helper function in order to deal with D-cache coloring.

With these changes I was able to squeeze out a mmap() just over
3.6GB in size in a 32-bit process.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
2006-03-17 14:41:03 -08:00
parent b5e7ae5dd0
commit a91690ddd0
4 changed files with 189 additions and 10 deletions
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190
arch/sparc64/kernel/sys_sparc.c
View File

@@ -82,9 +82,34 @@ static inline int straddles_64bit_va_hole(unsigned long start, unsigned long end
return 1;
}
#define COLOUR_ALIGN(addr,pgoff) \
((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
/* These functions differ from the default implementations in
* mm/mmap.c in two ways:
*
* 1) For file backed MAP_SHARED mmap()'s we D-cache color align,
* for fixed such mappings we just validate what the user gave us.
* 2) For 64-bit tasks we avoid mapping anything within 4GB of
* the spitfire/niagara VA-hole.
*/
static inline unsigned long COLOUR_ALIGN(unsigned long addr,
unsigned long pgoff)
{
unsigned long base = (addr+SHMLBA-1)&~(SHMLBA-1);
unsigned long off = (pgoff<<PAGE_SHIFT) & (SHMLBA-1);
return base + off;
}
static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
unsigned long pgoff)
{
unsigned long base = addr & ~(SHMLBA-1);
unsigned long off = (pgoff<<PAGE_SHIFT) & (SHMLBA-1);
if (base + off <= addr)
return base + off;
return base - off;
}
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags)
{
@@ -106,7 +131,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
if (test_thread_flag(TIF_32BIT))
task_size = 0xf0000000UL;
if (len > task_size || len >= VA_EXCLUDE_START)
if (unlikely(len > task_size || len >= VA_EXCLUDE_START))
return -ENOMEM;
do_color_align = 0;
@@ -125,11 +150,12 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
return addr;
}
if (len <= mm->cached_hole_size) {
if (len > mm->cached_hole_size) {
start_addr = addr = mm->free_area_cache;
} else {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
mm->free_area_cache = TASK_UNMAPPED_BASE;
}
start_addr = addr = mm->free_area_cache;
task_size -= len;
@@ -146,7 +172,7 @@ full_search:
addr = VA_EXCLUDE_END;
vma = find_vma(mm, VA_EXCLUDE_END);
}
if (task_size < addr) {
if (unlikely(task_size < addr)) {
if (start_addr != TASK_UNMAPPED_BASE) {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
@@ -154,7 +180,7 @@ full_search:
}
return -ENOMEM;
}
if (!vma || addr + len <= vma->vm_start) {
if (likely(!vma || addr + len <= vma->vm_start)) {
/*
* Remember the place where we stopped the search:
*/
@@ -170,6 +196,121 @@ full_search:
}
}
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long task_size = 0xf0000000UL;
unsigned long addr = addr0;
int do_color_align;
/* This should only ever run for 32-bit processes. */
BUG_ON(!test_thread_flag(TIF_32BIT));
if (flags & MAP_FIXED) {
/* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
*/
if ((flags & MAP_SHARED) &&
((addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)))
return -EINVAL;
return addr;
}
if (unlikely(len > task_size))
return -ENOMEM;
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = 1;
/* requesting a specific address */
if (addr) {
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
else
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (task_size - len >= addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
/* check if free_area_cache is useful for us */
if (len <= mm->cached_hole_size) {
mm->cached_hole_size = 0;
mm->free_area_cache = mm->mmap_base;
}
/* either no address requested or can't fit in requested address hole */
addr = mm->free_area_cache;
if (do_color_align) {
unsigned long base = COLOUR_ALIGN_DOWN(addr-len, pgoff);
addr = base + len;
}
/* make sure it can fit in the remaining address space */
if (likely(addr > len)) {
vma = find_vma(mm, addr-len);
if (!vma || addr <= vma->vm_start) {
/* remember the address as a hint for next time */
return (mm->free_area_cache = addr-len);
}
}
if (unlikely(mm->mmap_base < len))
goto bottomup;
addr = mm->mmap_base-len;
if (do_color_align)
addr = COLOUR_ALIGN_DOWN(addr, pgoff);
do {
/*
* Lookup failure means no vma is above this address,
* else if new region fits below vma->vm_start,
* return with success:
*/
vma = find_vma(mm, addr);
if (likely(!vma || addr+len <= vma->vm_start)) {
/* remember the address as a hint for next time */
return (mm->free_area_cache = addr);
}
/* remember the largest hole we saw so far */
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
/* try just below the current vma->vm_start */
addr = vma->vm_start-len;
if (do_color_align)
addr = COLOUR_ALIGN_DOWN(addr, pgoff);
} while (likely(len < vma->vm_start));
bottomup:
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
mm->cached_hole_size = ~0UL;
mm->free_area_cache = TASK_UNMAPPED_BASE;
addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
/*
* Restore the topdown base:
*/
mm->free_area_cache = mm->mmap_base;
mm->cached_hole_size = ~0UL;
return addr;
}
/* Try to align mapping such that we align it as much as possible. */
unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, unsigned long len, unsigned long pgoff, unsigned long flags)
{
@@ -213,6 +354,37 @@ unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, u
return addr;
}
/* Essentially the same as PowerPC... */
void arch_pick_mmap_layout(struct mm_struct *mm)
{
/*
* Fall back to the standard layout if the personality
* bit is set, or if the expected stack growth is unlimited:
*/
if (!test_thread_flag(TIF_32BIT) ||
(current->personality & ADDR_COMPAT_LAYOUT) ||
current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY ||
sysctl_legacy_va_layout) {
mm->mmap_base = TASK_UNMAPPED_BASE;
mm->get_unmapped_area = arch_get_unmapped_area;
mm->unmap_area = arch_unmap_area;
} else {
/* We know it's 32-bit */
unsigned long task_size = 0xf0000000UL;
unsigned long gap;
gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
if (gap < 128 * 1024 * 1024)
gap = 128 * 1024 * 1024;
if (gap > (task_size / 6 * 5))
gap = (task_size / 6 * 5);
mm->mmap_base = task_size - (gap & PAGE_MASK);
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
mm->unmap_area = arch_unmap_area_topdown;
}
}
asmlinkage unsigned long sparc_brk(unsigned long brk)
{
/* People could try to be nasty and use ta 0x6d in 32bit programs */